I think an iPhone 4, which is now free with a 2 year contract would be perfect for you - if you need to actually have a phone! Get the minimum plan for phone minutes and data usage (but monitor your minutes and data usage and adjust your plan if necessary - you use data services only when you connect to the Web through your phone carrier - WiFi usage doesn't use your provider's data services - you'll need to learn how to turn WiFi on and off when necessary - but that's easy or just leave it on WiFi all the time.

If you really don't need a Phone, then the new IPod Touch might be for you - no monthly charges, but the unit itself costs $s and you'd have to exclusively use WiFi for connection to the Web - but you'd have all the latest iPhone 5 features without the phone (camera too? Not sure).

Warning, if you are inquisitive and adventurous, the iPhone (or other Smartphone, but especially iPhone with all the free or inexpensive Apps) is absolutely addictive and will change your life! - no exaggeration!

Also, watch out if you have a current contract. Will you be breaking that to get "subsidized" phone from your carrier? If so, that may cost you $s. typically, you're entitled to a new subsidized phone every 2 years.

Good Luck